Library /sys$common/syshlp/nclhelp.hlb set, routing, circuit, reachable_address, LAN address  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Support: L2,End
    Default: 00-00-00-00-00-00 	 Value: ID

    A single LAN address to which an NPDU can be directed in order
    to reach an address that matches the address prefix of the parent
    reachable address entity. This attribute is supported only if the
    type characteristic is set to outbound on broadcast circuits only.
    A valid address is required here.

    You can modify this characteristic only when the entity is
    disabled.

    set [node node-id] routing circuit circuit-name reachable -
        address simplename lan address aa-00-04-00-xx-xx

    Example:

    set routing circuit csmacd-1 reachable address to-area4 -
        lan address aa-00-04-00-12-34